Printing mechanism



Jan. 5, 1960 F. w. PFL'EG'ER 2,919,641

PRINTING MECHANISM Filed March 7, 1957 7'/M//VG MEANS INVENTOR. 40

44 A fEg zerzik WFf/eger Armmvgx United States Patent PRINTING MECHANISMFrederick W. Pfleger, Pennsauken, N..l., assignor to Radio Corporationof America, a corporation of Delaware Application March 7, 1957, SerialNo. 644,576

7 Claims. (Cl. 101-93) This invention relates to printing mechanisms,and more particularly to rotary type printers.

In some known devices, a rotating type carrier or type wheel is haltedduring a printing operation by means of pawls and ratchets or the likeso that a hammer may subsequently strike a sheet of paper against acharacter on the surface of the type wheel Without the occurrence ofblur. In order to achieve high speeds, it is preferable to stop the typecarrier rapidly so that lost time may be minimized.

Therefore, it is an object of this invention to provide an improvedprinting mechanism of the rotary type which may operate at high speeds.

It is a further object of this invention to provide a novel printingmechanism which, by eliminating the need for any pawls or ratchets, issimply constructed.

In accordance with this invention, a type-carrying annular ring isrotated by a constantly rotating concentric shaft. The ring and shaftare coupled together by a resilient material, such as a spring. Theannular ring is of comparatively low mass and thickness so that itsmoment of inertia is small. By striking the ring with a hammer, therotating ring will halt due to the frictional force of the hammer uponthe ring (although the inner shaft continues to rotate), and a charactermay be imprinted upon a suitable sheet. Upon release of the hammer, thering resumes its original orientation with respect to the shaft due tothe springing effect of the resilient material.

The annular ring should be as thin and as lightweight as possible. Apreferred form is that of a thin, flexible nylon belt. The concentricshaft, with grooves and lands around its periphery, gives support to theflexible ring. The lands are located beneath the correspondingcharacters on the ring so as to give adequate support to the ring whenit is struck by a hammer. The grooves on the shaft act as oilreservoirs, so that the shaft is well lubricated. By using such aprinting mechanism, a hammer may strike the rotating ring and printwithout the occurrence of blur.

The novel features that are considered characteristic of this inventionare set forth with particularity in the appended claims. The inventionitself, however, both as to its organization and method of operation aswell as additional objects and advantages thereof will best beunderstood from the following description when read in connection withthe accompanying drawings, in which:

Figure l is a view transverse to the axis of rotation and partly incross-section of one embodiment of this invention utilizing a rubberblock as a resilient member;

Figure 2 is a view transverse to the axis of rotation and partly incross-section of an embodiment similar to that of Figure 1, but inmodified form utilizing a spring as a resilient member;

Figure 3 is a plan view of the embodiment shown in Figure 1 or in Figure2 illustrating a plurality of type carriers for use in practicing theinvention; and

Figure 4 is a plan view of a simplified spring means J 2,919,641Patented Jan. 5, 1960 for use with the plurality of type carriers shownin Figure 3.

With reference to Figure 1, a printing mechanism comprises a shaft 10rotating in a clockwise direction as viewed in this figure. Acircumferentially resilient member, such as a rubber block 12, ismounted in a groove in the shaft 10. The shaft It) is concentricallymounted within an annular ring 14. The ring 14 is coupled to the shaft10 by means of a positioning member 16 placed adjacent to the resilientmember, or rubber block 12. The outer surface of the annular ring 14contains a font 18 of printing characters. The annular ring 14 has a lowmoment of inertia, being constructed of a thin, lightweight material,such as nylon. Preferably, the ring 14 is so thin that it is flexibleand depends upon the shaft 10 for its support.

The lands 22 are located beneath the corresponding characters so as toprovide a suitable backing or support for the ring 14 when a characteris hit by a striking member. In grooves between each of the lands 22 arethe oil reservoirs 2t) which provide adequate lubrication, decreasingfriction, for reducing the moment of inertia of the printing mechanism,and hence reducing undersirable blur. An inked ribbon 24 and printinghammer 26 are suitably located a short distance away from the ring 14.

The operation of the embodiment, as shown in Figure 1, is as follows:

The shaft 10 rotates continuously, at a fixed speed, carrying with itthe annular ring 14 which normally rotates at the same speed, due to thepositioning member 16 coupling the ring 14 with the shaft 10. However,when it is desired to print a desired character onto a print receivingmaterial, such as paper 28, the hammer 26 is actuated so as to strikethe desired character on the annular ring 14. An imprint of thecharacter is printed by means of the ink ribbon 24 onto the paper 28which had been placed adjacent to the ribbon 24. The striking of thehammer 26 causes the annular ring 14 to come substantially immediatelyto a halt due to its negligible moment of inertia. Because the ring 14comes to a substantially immediate halt, the blur, if any, appearing onthe paper 28 is negligible. During the interval that the annular ring 14is halted, the shaft 10 continues to rotate, causing the positioningmember 16 to compress the rubber block 12. When the hammer 26 releases,the resilience of the rubber block 12 forces the positioning member 16back to its original location so that the ring 14 and the shaft 10 areoriented with respect to each other as they were initially.

With reference to Figure 2, there is shown a similar device operating ina similar manner. The shaft 10 rotates, as shown, in a clockwisedirection. A spring 30 is affixed to a sectorial cavity 32 in the shaft10. The annular ring 14 has a protuberance 16 projecting inwardly whichacts as a positioning member. When the ring 14 is halted by the actionof a print hammer, the positioning member 16 biases the spring 361, sothat, when the annular ring 14 is released, the spring 30 urges the ring14 in proper orientation with the shaft 10. Although no oil reservoirsare illustrated in Figure 2, it is understood that, for excellentperformance, suitable lubrication should be provided between the ringand shaft. Oil reservoirs, as shown in Figure .l, or other suitablelubricating means may be used.

With reference to Figure 3, there are shown a plurality of annular rings14 mounted in suitable fashion for use ice as a multiple characterprinter, such as a line-at-a-time suitable means, such as by gears 36.Coded information for printing an entire line may be placed into acontrol unit 38 for operating the hammers 26 so that, upon onerevolution of the shaft 10, a line is printed. Each character appearingon the font 13 of an annular ring 14 is printed when that characterapproaches its respective hammer 26. Any suitable controlling mechanismmay be used. To further illustrate the invention, as shown in Figure 3,assume that it is desired to print a message reading abcabcabca. Theinformation for this message is stored in the control unit. As the shaft10 rotates, so that the as appear under the hammers 26, the first,fourth, seventh and tenth hammers are actuated, causin as to be printedonto the paper at the first, fourth, seventh and tenth positions in aline. The shaft continues rotation, and when bs appear under theharnmers, the second, fifth, and eighth hammers are actuated. Similarly,at a short interval, the third, sixth and ninth hammers cause cs to beimprinted onto the paper 28. The printed message then reads: abcabcabca.During one revolution of the shaft, one line is imprinted on a sheet ofpaper 23. During the next revolution, information regarding the nextline may be fed into the control unit 38 and the paper 28 may beadvanced. During the following revolution, 21 second line may be printedand again during the next revolution, new information may be fed intothe control unit 38. The cycle may be repeated for as many times asdesired.

There is shown, in Figure 4, a suitable spring means 40 for use in theprinting mechanism shown in Figure 3. The spring means 40 is constructedof one piece of spring steel, so cut so that ten fingers 42 extend froma common handle 44. Each finger is associated with a correspondingannular ring 14. Such a unitary spring means is easily constructed.

The annular ring 14 may be constructed of a thin lightweight material,such as nylon. However, the annular ring 14 may also be constructed ofother suitable materials, especially those which provide a thin ring ofrelatively low moment of inertia. Since the moment of inertia of anannular cylinder is /21i-5h(r r where 5 is the density, h is the width,and r and r are the outer and inner radii, respectively, of the annularcylinder, it is preferable to use a lightweight material. However, avery thin steel ring may be used. The steel ring may be made extremelythin, tending to compensate for the greater density of steel over nylon,and the ring still may have the requisite mechanical properties.

It will be further understood, of course, that the invention is notlimited to the particular embodiment shown and described, but is capableof various modifications and further embodiments without departing fromthe scope of the appended claims.

What is claimed is:

1. A printing mechanism comprising an annular ring having a low momentof inertia adapted to hold type, said ring being so thin as to beflexible, a drive shaft adapted to be continuously rotated within and tosupport said ring, said shaft having friction-reducing oil reservoirsabout the periphery of said shaft, and a circumferentially resilientmember coupling said shaft to said ring.

2. A printing wheel comprising a ring adapted to hold type, a driveshaft adapted to be continuously rotated within and supporting saidring, said shaft having friction-reducing oil reservoirs about theperiphery of said shaft, a circumferentially resilient member couplingsaid shaft to said ring, and means interrupting the rotation of saidring, when said shaft is continuously rotating, by printing a characteron a print receiving material.

3. A printing mechanism for printing on a print-receiving medium andcomprising a thin, flexible, annular ring carrying a plurality of typefaces, a drive shaft, means for continuously rotating said drive shaftwithin, concentric with, and in supporting relationship to said ring, a.circumferentially resilient coupling between said ring and said shaftfor rotatably driving said ring by rotating said drive shaft, a printhammer, and means for impelling said hammer against any said type facewith said printing medium interposed between said type face and mer,said type face being backed and sup-ported by said shaft, said mediumthereby receiving a printing impression, said circumferentiallyresilient coupling affording a momentary stop of said ring withoutstopping shaft when any said impression is thus made and a ng said ringto resume its initial position relative to said shaft before the nextsucceeding impression is made.

4. A printing mechanism as claimed in claim 3, said coupling includingan inwardly projecting stop member carried by said ring.

5. A printing mechanism as claimed in claim 3, said coupling comprisinga spring, said ring carrying an inwardly projecting stop member againstwhich said spring is biased for providing the said drive coupling.

6. A printing mechanism as claimed in claim 3, said coupling comprisinga rubber block, said shaft having a groove in which said block ismounted, and an inwardly projecting stop member carried by said ringagainst which said block bears for providing said coupling.

7. A printing mechanism for printing on a print-receiving medium andcomprising a plurality of thin, flexible, annular rings each carrying aplurality of type faces, a drive shaft, means for continuously rotatingsaid drive shaft within and concentric to said rings, said shaftcarrying said rings side-by-side, a plurality of circumferentiallyresilient couplings respectively between said rings and said shaft, aplurality of print hammers corresponding respectively to said printwheels, and means for impelling selected hammers against any selectedtype face with said printing medium interposed between said type faceand. said hammer, said type face being supported and backed by saidshaft, said printing medium thereby receiving a printing impression,said circumferentially resilient couplings affording driving couplingsbetween said drive shaft and said respective rings for driving the ringsconcentrically for rotation with said shaft and affording a momentarystop of the rotation of any shaft when a said impression is made by thecorresponding print hammer and causing the corresponding ring to assumeits initial position in relation to said shaft before the nextsucceeding type face of that ring is in position for effecting animpression.

References fitted in the file of this patent UNITED STATES PATENTS1,606,190 Sharp Nov. 9, 1926 1,646,576 Castan Oct. 25, 1927 1,675,969Bull July 3, 1928 2,036,027 Ecker Mar. 31, 1936 2,157,035 Torkelson May2, 1939 2,211,794 Rohland Aug. 20, 1940 2,468,427 Cheeseman Apr. 26,1949 2,603,153 Warren July 15, 1952 2,631,535 Mumma Mar. 17, 19532,737,883 Crawford Mar. 13, 1956 2,787,952 Roche Apr. 9, 1957 2,805,620Rosen Sept. 10, 1957

